Microsoft Edge
Control the behavior for the cancel dialog produced by the beforeunload event (obsolete)
Supported on Microsoft Edge version 118-130, Windows 7 or later
What it does
OBSOLETE: This policy is obsolete and doesn't work after Microsoft Edge 130. This policy provides a temporary opt-out for two related fixes to the behavior of the confirmation dialog that’s shown by the beforeunload event. If you've enabled this policy, the new (correct) behavior is used. If you've disabled this policy, the old (legacy) behavior is used. If you haven't configured this policy, the default behavior is used. Note: This policy is a temporary workaround and is going to be removed in a future release. New and correct behavior: In `beforeunload`, calling `event.preventDefault()` triggers the confirmation dialog. Setting `event.returnValue` to the empty string doesn’t trigger the confirmation dialog. Old and legacy behavior: In `beforeunload`, calling `event.preventDefault()` doesn’t trigger the confirmation dialog. Setting `event.returnValue` to the empty string triggers the confirmation dialog.
What it writes
- Hive
- HKEY_LOCAL_MACHINE or HKEY_CURRENT_USER
- Registry key
Software\Policies\Microsoft\Edge- Value name
BeforeunloadEventCancelByPreventDefaultEnabled- When enabled
- DWORD 1
- When disabled
- DWORD 0
Configure and deploy
Choose a state; the output below is generated from the template for exactly that.
Enabled · Computer · template defaults
Registry file (.reg)
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Edge]
"BeforeunloadEventCancelByPreventDefaultEnabled"=dword:00000001
PowerShell
$ErrorActionPreference = 'Stop'
function Set-RegistryValue {
param(
[Parameter(Mandatory = $true)][string] $Path,
[Parameter(Mandatory = $true)][string] $Name,
[Parameter(Mandatory = $true)][string] $PropertyType,
[Parameter(Mandatory = $true)][object] $Value
)
if (-not (Test-Path -LiteralPath $Path)) {
New-Item -Path $Path -Force | Out-Null
}
New-ItemProperty -LiteralPath $Path -Name $Name -PropertyType $PropertyType -Value $Value -Force | Out-Null
}
function Remove-RegistryValue {
param(
[Parameter(Mandatory = $true)][string] $Path,
[Parameter(Mandatory = $true)][string] $Name
)
if (Test-Path -LiteralPath $Path) {
Remove-ItemProperty -LiteralPath $Path -Name $Name -Force -ErrorAction SilentlyContinue
}
}
function Clear-RegistryKeyValues {
param(
[Parameter(Mandatory = $true)][string] $Path
)
if (-not (Test-Path -LiteralPath $Path)) {
return
}
foreach ($propertyName in (Get-Item -LiteralPath $Path).Property) {
Remove-ItemProperty -LiteralPath $Path -Name $propertyName -Force -ErrorAction SilentlyContinue
}
}
# Policy: Control the behavior for the cancel dialog produced by the beforeunload event (obsolete)
# Name: BeforeunloadEventCancelByPreventDefaultEnabled
# Scope: Machine
# State: Enabled
# Source: msedge.admx
Set-RegistryValue -Path 'Registry::HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Edge' -Name 'BeforeunloadEventCancelByPreventDefaultEnabled' -PropertyType 'DWord' -Value 1
- The OMA-URI is an inferred ADMX-backed Policy CSP candidate derived from the source ADMX file name and policy name.
- Some Microsoft policies use built-in Policy CSP pages whose area names don't match the ADMX file name, so verify the candidate against Microsoft Learn before deployment.
ADMX profile candidate (OMA-URI)
./Device/Vendor/MSFT/Policy/Config/ADMX_msedge/BeforeunloadEventCancelByPreventDefaultEnabledADMX SyncML candidate
<SyncML xmlns="SYNCML:SYNCML1.2">
<SyncBody>
<Replace>
<CmdID>1</CmdID>
<Item>
<Meta>
<Format>chr</Format>
<Type>text/plain</Type>
</Meta>
<Target>
<LocURI>./Device/Vendor/MSFT/Policy/Config/ADMX_msedge/BeforeunloadEventCancelByPreventDefaultEnabled</LocURI>
</Target>
<Data><enabled/></Data>
</Item>
</Replace>
<Final/>
</SyncBody>
</SyncML>Intune remediation scripts
Detection
$ErrorActionPreference = 'Stop'
$reasons = [System.Collections.Generic.List[string]]::new()
function Test-RegistryValueExists {
param(
[Parameter(Mandatory = $true)][string] $Path,
[Parameter(Mandatory = $true)][string] $Name
)
if (-not (Test-Path -LiteralPath $Path)) {
return $false
}
return $null -ne (Get-ItemProperty -LiteralPath $Path -Name $Name -ErrorAction SilentlyContinue)
}
function Test-RegistryValueEquals {
param(
[Parameter(Mandatory = $true)][string] $Path,
[Parameter(Mandatory = $true)][string] $Name,
[Parameter(Mandatory = $true)][string] $Kind,
[Parameter(Mandatory = $true)][object] $Expected
)
if (-not (Test-Path -LiteralPath $Path)) {
return $false
}
$valueObject = Get-ItemProperty -LiteralPath $Path -Name $Name -ErrorAction SilentlyContinue
if ($null -eq $valueObject) {
return $false
}
$actual = $valueObject.$Name
switch ($Kind) {
'String' { return [string]$actual -ceq [string]$Expected }
'ExpandString' { return [string]$actual -ceq [string]$Expected }
'DWord' { return [uint32]$actual -eq [uint32]$Expected }
'QWord' { return [uint64]$actual -eq [uint64]$Expected }
'MultiString' {
$actualArray = @($actual)
$expectedArray = @($Expected)
if ($actualArray.Count -ne $expectedArray.Count) { return $false }
for ($index = 0; $index -lt $actualArray.Count; $index++) {
if ([string]$actualArray[$index] -cne [string]$expectedArray[$index]) { return $false }
}
return $true
}
'Binary' {
$actualArray = [byte[]]$actual
$expectedArray = [byte[]]$Expected
if ($actualArray.Length -ne $expectedArray.Length) { return $false }
for ($index = 0; $index -lt $actualArray.Length; $index++) {
if ($actualArray[$index] -ne $expectedArray[$index]) { return $false }
}
return $true
}
default { return [string]$actual -ceq [string]$Expected }
}
}
# Policy: Control the behavior for the cancel dialog produced by the beforeunload event (obsolete)
# Name: BeforeunloadEventCancelByPreventDefaultEnabled
# Scope: Machine
# State: Enabled
# Source: msedge.admx
$isMatch = Test-RegistryValueEquals -Path 'Registry::HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Edge' -Name 'BeforeunloadEventCancelByPreventDefaultEnabled' -Kind 'DWord' -Expected 1
if (-not $isMatch) {
$reasons.Add('Value mismatch: HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Edge\BeforeunloadEventCancelByPreventDefaultEnabled') | Out-Null
}
if ($reasons.Count -eq 0) {
Write-Output 'Compliant'
exit 0
}
$reasons | ForEach-Object { Write-Output $_ }
exit 1
Remediation
$ErrorActionPreference = 'Stop'
function Set-RegistryValue {
param(
[Parameter(Mandatory = $true)][string] $Path,
[Parameter(Mandatory = $true)][string] $Name,
[Parameter(Mandatory = $true)][string] $PropertyType,
[Parameter(Mandatory = $true)][object] $Value
)
if (-not (Test-Path -LiteralPath $Path)) {
New-Item -Path $Path -Force | Out-Null
}
New-ItemProperty -LiteralPath $Path -Name $Name -PropertyType $PropertyType -Value $Value -Force | Out-Null
}
function Remove-RegistryValue {
param(
[Parameter(Mandatory = $true)][string] $Path,
[Parameter(Mandatory = $true)][string] $Name
)
if (Test-Path -LiteralPath $Path) {
Remove-ItemProperty -LiteralPath $Path -Name $Name -Force -ErrorAction SilentlyContinue
}
}
function Clear-RegistryKeyValues {
param(
[Parameter(Mandatory = $true)][string] $Path
)
if (-not (Test-Path -LiteralPath $Path)) {
return
}
foreach ($propertyName in (Get-Item -LiteralPath $Path).Property) {
Remove-ItemProperty -LiteralPath $Path -Name $propertyName -Force -ErrorAction SilentlyContinue
}
}
# Policy: Control the behavior for the cancel dialog produced by the beforeunload event (obsolete)
# Name: BeforeunloadEventCancelByPreventDefaultEnabled
# Scope: Machine
# State: Enabled
# Source: msedge.admx
Set-RegistryValue -Path 'Registry::HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Edge' -Name 'BeforeunloadEventCancelByPreventDefaultEnabled' -PropertyType 'DWord' -Value 1
History 37 retained releases
- 150.0.4078.8016 Jul 2026
- Already present in the first release ChangeIntel keeps.
36 later releases left it unchanged.
Template
- Internal name
BeforeunloadEventCancelByPreventDefaultEnabled- Namespace
Microsoft.Policies.Edge- Template file
msedge.admx- Release
- Microsoft Edge 155.0.4283.62 · file set
0a733b0040dbbf02…
Definition, editor controls and support
Definition
<policy class="Both" displayName="$(string.BeforeunloadEventCancelByPreventDefaultEnabled)" explainText="$(string.BeforeunloadEventCancelByPreventDefaultEnabled_Explain)" key="Software\Policies\Microsoft\Edge" name="BeforeunloadEventCancelByPreventDefaultEnabled" presentation="$(presentation.BeforeunloadEventCancelByPreventDefaultEnabled)" valueName="BeforeunloadEventCancelByPreventDefaultEnabled" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
<parentCategory ref="Microsoft.Policies.Edge:microsoft_edge" />
<supportedOn ref="Microsoft.Policies.Edge:OBSOLETE_WIN7_V118_V130" />
<enabledValue>
<decimal value="1" />
</enabledValue>
<disabledValue>
<decimal value="0" />
</disabledValue>
</policy>Editor controls
<presentation id="BeforeunloadEventCancelByPreventDefaultEnabled" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />Supported platforms and category
Microsoft.Policies.Edge:category:microsoft_edge
<category displayName="$(string.microsoft_edge)" name="microsoft_edge" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
Microsoft.Policies.Edge:definition:OBSOLETE_WIN7_V118_V130
<definition displayName="$(string.OBSOLETE_WIN7_V118_V130)" name="OBSOLETE_WIN7_V118_V130" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
Microsoft.Policies.Edge:category:microsoft_edge
<category displayName="$(string.microsoft_edge)" name="microsoft_edge" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
<strings><string id="Microsoft.Policies.Edge:microsoft_edge">Microsoft Edge</string></strings>
Microsoft.Policies.Edge:definition:OBSOLETE_WIN7_V118_V130
<definition displayName="$(string.OBSOLETE_WIN7_V118_V130)" name="OBSOLETE_WIN7_V118_V130" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
<strings><string id="Microsoft.Policies.Edge:OBSOLETE_WIN7_V118_V130">Microsoft Edge version 118-130, Windows 7 or later</string></strings>